Is integrity our most important trait?

Consequences - detail

"If I could teach only one value to live by, it would be this: Success will come and go, but integrity is forever. Integrity means doing the right thing at all times and in all circumstances, whether or not anyone is watching. It takes having the courage to do the right thing, no matter what the consequences will be." Amy Rees Anderson - article in Forbes 28 Nov 2012
Ms Anderson was writing in Forbes for a corporate audience though I could see such an astute observation fitting in to a short piece I'd been thinking on about how integrity is central to our being with empathy its emotional realisation. 
Anderson's quote so clearly defines integrity. My piece was going to take a more philosophical path when I first found and saved the above quote. Then the latest massacre of innocents in the United States emerged and the horrific details numbed the senses. Most victims were small children, most were  shot over and over receiving multiple wounds from the type of weaponry and ballistics intended to produce devastation in the flesh and subsequent certain death. Death for these victims, these harmless babies and defenceless adults, one hopes at least was mercifully fast. A psychopath, an aggrieved outsider, with access to a powerful arsenal and the desire to use it to exact revenge for imagined harm must be the last straw.   

How do we know it? What is it? Is integrity within us and could we recognise it? If there is anything in life we may remember with regret perhaps it is because we remember we failed to act with integrity when we might have, could have or should have. Perhaps we did not go to the aid of a fellow student being bullied. Or, worse participated in the shameful behaviour because it put the spot light onto another. Perhaps we simply remained a by stander. There are levels of integrity, from not cheating on a test to risking death in the attempt to protect the life of another. 

Shielding of small children in danger with your own body and giving your own life attempting to defend them is acting with integrity of such selfless heroism it escapes proper description other than we can only be in awe of it. These teachers attempted to disarm their assailant, attempted to shield the children from the worst of nightmares. They acted with courage and honour in unpredictable circumstances.

The thing with integrity, it costs nothing and can cost everything all at once whilst remaining the right course of action. The citizens of the United States need to act with courage and honour by facing up to the truth. The right to bare arms and the proliferation of arms in private possession in the US is anathema to the modern state. They and their legislature now must do what is right, no matter the consequences, because it is the right thing to do and because "...integrity is forever".